The present invention relates to a use system and application of an electric power storing secondary battery that is effective for load leveling.
A load leveling system which stores electric power in the nighttime and uses it in the daytime employing an electric power storing secondary battery, as disclosed in Japanese Application Patent Laid-Open Publication Nos. Hei 8-287958 (1996), Hei 8-138731 (1996), and Hei 11-233137 (1999), is expected to be used widely in future because the system is very much effective for diminishing the necessity for constructing a generating facility and transmission/transformation equipment corresponding to the peak power in the daytime and for improving the utilization factor of the generating facility and transmission/transformation equipment.
An electric power storing secondary battery could be located in a substation in the suburb of a city but more locations are needed for expanded utilization. Besides, since the locations are desired to be closer to the electric power consumers for minimizing transmission equipment, it is preferred that the electric power storing secondary battery be installed near at hand an electric power consumer. If, however, the electric power consumer is to own the electric power storing secondary battery and utilize it in a building, apartment house, or solitary island, the electric power consumer must have knowledge and capability of operating, maintaining and managing the electric power storing secondary battery. This has been an obstacle to the popularization of the electric power storing secondary battery. This problem is particularly serious if a sodium-sulfur battery or the like that contains hazardous material is used as the electric power storing secondary battery, that is, a qualified hazardous material operator is required for the operation because of the regulation of the Fire Fighting Law. This has made it difficult for a power user to operate, maintain and manage the electric power storing secondary battery.
If an electric power consumer is to employ an electric power storing secondary battery, it is important for the popularization that the purchase cost of the electric power storing secondary battery can be covered with the difference between the daytime power fee and the nighttime power fee. In case an electric power consumer is to purchase an electric power storing secondary battery, however, the electric power consumer has to make an initial investment in the equipment and, although it could be recovered after years of continued utilization, this has been an obstacle to the popularization.
There is another problem. If the electric power storing secondary battery is to be installed at a place like a building, apartment house, or solitary island, where multiple electric power consumers are resident, more batteries and wider space are required so that each electric power consumer is equipped with individual electric power storing secondary battery.